Local Diurnal Profiles:
The temperature profile for Eugene days like today is complicated and typically is defined by three conditions:
- The 6-7 am minimum temperature
- The temperature rise until about noon - this depends on
if there are a) any early morning clouds, b) wind direction (usually calm) and c) the relative humidity of the air - dry air warms faster (sometimes significantly faster - and you should know why this is).
- Whether or not a North-West Wind kicks up.
The following graph shows the temperature profile for Friday
April 26, 2013. Measurements are every 15 minutes so 4 ticks per hour on the X-axis. The morning slope is about 4 degrees per hour. Then the temperature profile is strongly modified (by wind).
The next profile is for yesterday Apr 30, 2013:
The small dips in the morning rise are due to clouds.
The beginning temperature was about 10 degrees lower
than on April 26. This is because the dew point was much
lower, allowing the nighttime surface to cool much more.
Total variation on April 26 was 32 degrees (47 to 79)
Total variation on April 30 was 22 degrees (36 to 58).
So on sunny days this time of year the variations are usually
in this range.
Today's morning low was also 36. Why will the temperature be
higher to day than yesterday?
- Maybe it won't be but that is not the forecasdt ...
- There will likely be no morning partial cloudiness to
interrupt the temp profile so that should add a few degrees - but
how many degrees?
- at 10:30 am yesterday the temperature was 51.6
- at 10:30 am today the temperature was 57.7
Why is it predicted to be warmer today (in some cases the
forecast is much warmer)?
Morning temperature profile should be higher than yesterday (so
far it not).
An East-NE wind might kick in to spike up the temp. profile. (I think this is likely to happen tomorrow). Or the NNW wind may
not happen this afternoon.
The air will be drier today than yesterday.
My prediction for today is yesterday's temp + 5 = 63. If I am hosed, this is because something will change a lot afternoon (i.e wind)
Right now, it doesn't even look like it will break 60.
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